The following experimental approaches will be undertaken: 1. further examination of the effects of inhibitors of tryptophan hydroxylase and tyrosine hydroxylase on growth hormone secretion, with specificity increased for specific CNS activity, 2. attempts to overcome the changes with other substances that stimulate or inhibit growth hormone secretion, including acute administration of agonists, 3. attempts to examine secretion of other pituitary hormones to determine specificity of effects for growth hormone secretion, specifically prolactin, thyroid hormones, gonadal hormones.